1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #ifndef lint
36 #if 0
37 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
38 #endif
39 #endif /* not lint */
40 #include <sys/cdefs.h>
41 #include <sys/param.h>
42 #include "shell.h"
43 #include "output.h"
44 #include "memalloc.h"
45 #include "error.h"
46 #include "mystring.h"
47 #include "expand.h"
48 #include <stdlib.h>
49 #include <unistd.h>
50
51 static void
badalloc(const char * message)52 badalloc(const char *message)
53 {
54 write(2, message, strlen(message));
55 abort();
56 }
57
58 /*
59 * Like malloc, but returns an error when out of space.
60 */
61
62 pointer
ckmalloc(size_t nbytes)63 ckmalloc(size_t nbytes)
64 {
65 pointer p;
66
67 if (!is_int_on())
68 badalloc("Unsafe ckmalloc() call\n");
69 p = malloc(nbytes);
70 if (p == NULL)
71 error("Out of space");
72 return p;
73 }
74
75
76 /*
77 * Same for realloc.
78 */
79
80 pointer
ckrealloc(pointer p,int nbytes)81 ckrealloc(pointer p, int nbytes)
82 {
83 if (!is_int_on())
84 badalloc("Unsafe ckrealloc() call\n");
85 p = realloc(p, nbytes);
86 if (p == NULL)
87 error("Out of space");
88 return p;
89 }
90
91 void
ckfree(pointer p)92 ckfree(pointer p)
93 {
94 if (!is_int_on())
95 badalloc("Unsafe ckfree() call\n");
96 free(p);
97 }
98
99
100 /*
101 * Make a copy of a string in safe storage.
102 */
103
104 char *
savestr(const char * s)105 savestr(const char *s)
106 {
107 char *p;
108 size_t len;
109
110 len = strlen(s);
111 p = ckmalloc(len + 1);
112 memcpy(p, s, len + 1);
113 return p;
114 }
115
116
117 /*
118 * Parse trees for commands are allocated in lifo order, so we use a stack
119 * to make this more efficient, and also to avoid all sorts of exception
120 * handling code to handle interrupts in the middle of a parse.
121 *
122 * The size 496 was chosen because with 16-byte alignment the total size
123 * for the allocated block is 512.
124 */
125
126 #define MINSIZE 496 /* minimum size of a block. */
127
128
129 struct stack_block {
130 struct stack_block *prev;
131 /* Data follows */
132 };
133 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
134
135 static struct stack_block *stackp;
136 char *stacknxt;
137 int stacknleft;
138 char *sstrend;
139
140
141 static void
stnewblock(int nbytes)142 stnewblock(int nbytes)
143 {
144 struct stack_block *sp;
145 int allocsize;
146
147 if (nbytes < MINSIZE)
148 nbytes = MINSIZE;
149
150 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
151
152 INTOFF;
153 sp = ckmalloc(allocsize);
154 sp->prev = stackp;
155 stacknxt = SPACE(sp);
156 stacknleft = allocsize - (stacknxt - (char*)sp);
157 sstrend = stacknxt + stacknleft;
158 stackp = sp;
159 INTON;
160 }
161
162
163 pointer
stalloc(int nbytes)164 stalloc(int nbytes)
165 {
166 char *p;
167
168 nbytes = ALIGN(nbytes);
169 if (nbytes > stacknleft)
170 stnewblock(nbytes);
171 p = stacknxt;
172 stacknxt += nbytes;
173 stacknleft -= nbytes;
174 return p;
175 }
176
177
178 void
stunalloc(pointer p)179 stunalloc(pointer p)
180 {
181 if (p == NULL) { /*DEBUG */
182 write(STDERR_FILENO, "stunalloc\n", 10);
183 abort();
184 }
185 stacknleft += stacknxt - (char *)p;
186 stacknxt = p;
187 }
188
189
190 char *
stsavestr(const char * s)191 stsavestr(const char *s)
192 {
193 char *p;
194 size_t len;
195
196 len = strlen(s);
197 p = stalloc(len + 1);
198 memcpy(p, s, len + 1);
199 return p;
200 }
201
202
203 void
setstackmark(struct stackmark * mark)204 setstackmark(struct stackmark *mark)
205 {
206 mark->stackp = stackp;
207 mark->stacknxt = stacknxt;
208 mark->stacknleft = stacknleft;
209 /* Ensure this block stays in place. */
210 if (stackp != NULL && stacknxt == SPACE(stackp))
211 stalloc(1);
212 }
213
214
215 void
popstackmark(struct stackmark * mark)216 popstackmark(struct stackmark *mark)
217 {
218 struct stack_block *sp;
219
220 INTOFF;
221 while (stackp != mark->stackp) {
222 sp = stackp;
223 stackp = sp->prev;
224 ckfree(sp);
225 }
226 stacknxt = mark->stacknxt;
227 stacknleft = mark->stacknleft;
228 if (stacknleft != 0)
229 sstrend = stacknxt + stacknleft;
230 else
231 sstrend = stacknxt;
232 INTON;
233 }
234
235
236 /*
237 * When the parser reads in a string, it wants to stick the string on the
238 * stack and only adjust the stack pointer when it knows how big the
239 * string is. Stackblock (defined in stack.h) returns a pointer to a block
240 * of space on top of the stack and stackblocklen returns the length of
241 * this block. Growstackblock will grow this space by at least one byte,
242 * possibly moving it (like realloc). Grabstackblock actually allocates the
243 * part of the block that has been used.
244 */
245
246 static void
growstackblock(int min)247 growstackblock(int min)
248 {
249 char *p;
250 int newlen;
251 char *oldspace;
252 int oldlen;
253 struct stack_block *sp;
254 struct stack_block *oldstackp;
255
256 if (min < stacknleft)
257 min = stacknleft;
258 if ((unsigned int)min >=
259 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
260 error("Out of space");
261 min += stacknleft;
262 min += ALIGN(sizeof(struct stack_block));
263 newlen = 512;
264 while (newlen < min)
265 newlen <<= 1;
266 oldspace = stacknxt;
267 oldlen = stacknleft;
268
269 if (stackp != NULL && stacknxt == SPACE(stackp)) {
270 INTOFF;
271 oldstackp = stackp;
272 stackp = oldstackp->prev;
273 sp = ckrealloc((pointer)oldstackp, newlen);
274 sp->prev = stackp;
275 stackp = sp;
276 stacknxt = SPACE(sp);
277 stacknleft = newlen - (stacknxt - (char*)sp);
278 sstrend = stacknxt + stacknleft;
279 INTON;
280 } else {
281 newlen -= ALIGN(sizeof(struct stack_block));
282 p = stalloc(newlen);
283 if (oldlen != 0)
284 memcpy(p, oldspace, oldlen);
285 stunalloc(p);
286 }
287 }
288
289
290
291 /*
292 * The following routines are somewhat easier to use that the above.
293 * The user declares a variable of type STACKSTR, which may be declared
294 * to be a register. The macro STARTSTACKSTR initializes things. Then
295 * the user uses the macro STPUTC to add characters to the string. In
296 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
297 * grown as necessary. When the user is done, she can just leave the
298 * string there and refer to it using stackblock(). Or she can allocate
299 * the space for it using grabstackstr(). If it is necessary to allow
300 * someone else to use the stack temporarily and then continue to grow
301 * the string, the user should use grabstack to allocate the space, and
302 * then call ungrabstr(p) to return to the previous mode of operation.
303 *
304 * USTPUTC is like STPUTC except that it doesn't check for overflow.
305 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
306 * is space for at least one character.
307 */
308
309 static char *
growstrstackblock(int n,int min)310 growstrstackblock(int n, int min)
311 {
312 growstackblock(min);
313 return stackblock() + n;
314 }
315
316 char *
growstackstr(void)317 growstackstr(void)
318 {
319 int len;
320
321 len = stackblocksize();
322 return (growstrstackblock(len, 0));
323 }
324
325
326 /*
327 * Called from CHECKSTRSPACE.
328 */
329
330 char *
makestrspace(int min,char * p)331 makestrspace(int min, char *p)
332 {
333 int len;
334
335 len = p - stackblock();
336 return (growstrstackblock(len, min));
337 }
338
339
340 char *
stputbin(const char * data,size_t len,char * p)341 stputbin(const char *data, size_t len, char *p)
342 {
343 CHECKSTRSPACE(len, p);
344 memcpy(p, data, len);
345 return (p + len);
346 }
347
348 char *
stputs(const char * data,char * p)349 stputs(const char *data, char *p)
350 {
351 return (stputbin(data, strlen(data), p));
352 }
353